1. Field of the invention
This invention relates to a laser oscillator. More specifically, it relates to a laser tube holder which supports the laser tube in an axial flow type gas laser oscillator.
2. Description of the Related Art
In an axial flow type laser oscillator, in order to increase the output the length of the laser tube is increased, and the laser tube is divided into a number of sections, with electrical discharges in each section to excite laser oscillations. In a configuration in which, as described above, there are electrical discharges in a number of sections of a laser tube, in order to supply laser gas to each section and to remove laser gas from each section, the sections of the laser tube are separated. The separated sections of the laser tube have supply openings for the supply of laser gas, and there are exhaust tubes between the laser tube sections to remove laser gas. The said laser tube and exhaust tubes are connected through suitable joint members.
In an axial flow type laser oscillator with a configuration such as is described above, it is important that the entire laser tube be aligned along a single straight line. If the linearity of the laser tube is poor and the discrepancy between the axis of the laser tube and the laser beam axis becomes large, then the laser beam mode pattern, can be causing a drop in output.
Consequently, in the prior art, in order to make the laser beam axis coincide with the laser tube axis, the joint members which support a connecting portion between the laser tube and the exhaust tube separated from the laser tube are mounted on holder plates. Various configurations have been used to make the axis of these joint members coincident with the laser beam axis. However, in the conventional apparatus, when the joint members are fixed to the holder plates it is easy for a discrepancy to occur between the axes of the joint members and the laser beam axis, and adjustment is very difficult.